U.S. patent application number 15/319902 was filed with the patent office on 2017-05-25 for covered stent and preparation method therefor.
The applicant listed for this patent is BCM Co., Ltd.. Invention is credited to Byung Cheol MYUNG.
Application Number | 20170143467 15/319902 |
Document ID | / |
Family ID | 54341621 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170143467 |
Kind Code |
A1 |
MYUNG; Byung Cheol |
May 25, 2017 |
COVERED STENT AND PREPARATION METHOD THEREFOR
Abstract
Disclosed is a covered stent having bending characteristics,
capable of maintaining a bent state and preventing a lesion from
invading into the covered stent by solving the problem of a
conventional stent having bending characteristics. The present
invention provides a stent, wherein pieces of PTFE tape made of the
same material can be prevented from being separated from each other
to be maintained only through partial adhesion on the inside and
outside of a cylindrical stent, invasion of the lesion can be
prevented since the state where an entire outer surface of the
stent is wrapped with the PTFE tape can be maintained, and the bent
state of the cylindrical stent can be freely maintained since the
PTFE tape located on the outside and the cylindrical stent can
maintain a free state with each other by allowing no PTFE tape at a
part of the inside of the cylindrical stent.
Inventors: |
MYUNG; Byung Cheol;
(Gyeonggi-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BCM Co., Ltd. |
Gyeonggi-do |
|
KR |
|
|
Family ID: |
54341621 |
Appl. No.: |
15/319902 |
Filed: |
July 10, 2015 |
PCT Filed: |
July 10, 2015 |
PCT NO: |
PCT/KR2015/007167 |
371 Date: |
December 19, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/90 20130101; A61F
2230/0069 20130101; A61L 2420/08 20130101; A61L 2420/02 20130101;
A61F 2002/045 20130101; A61F 2/89 20130101; A61F 2250/0004
20130101; A61F 2/07 20130101; A61F 2002/072 20130101; A61F 2240/001
20130101; A61F 2220/0075 20130101; A61F 2/04 20130101; A61L 31/14
20130101; A61L 31/10 20130101; A61L 31/10 20130101; C08L 83/04
20130101; A61L 31/10 20130101; C08L 27/18 20130101 |
International
Class: |
A61F 2/04 20060101
A61F002/04; A61L 31/14 20060101 A61L031/14; A61L 31/10 20060101
A61L031/10; A61F 2/89 20060101 A61F002/89; A61F 2/90 20060101
A61F002/90 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2014 |
KR |
10-2014-0087700 |
Claims
1. A covered stent having bending characteristics, the covered
stent being prepared by using a cylindrical stent, wherein a PTFE
tape is provided at a section with an interval on an inside of the
cylindrical stent such that the PTFE tape and a PTFE tape that is
provided on an outside of the cylindrical stent remain bonded to
each other, whereas the cylindrical stent remains free at the
interval at which no PTFE tape is provided on the inside of the
cylindrical stent, so rhombic openings of the cylindrical stent
that are formed by weaving wires alternatively with a plurality of
interlocking portions and a plurality of intersection portions are
changeable in size by external force.
2. The covered stent of claim 1, wherein the interval at which no
PTFE tape is provided on the inside of the cylindrical stent is
provided in plural.
3. The covered stent of claim 1, wherein when providing the PTFE
tape, the interval at which no PTFE tape is provided on the inside
of the cylindrical stent is increased or reduced in width.
4. The covered stent of claim 1, wherein when a plurality of
intervals at which no PTFE tape is provided on the inside of the
cylindrical stent is provided, the intervals are different from
each other in width.
5. The covered stent of claim 1, wherein the section at which the
PTFE tape is provided on the inside of the cylindrical stent is
provided in plural.
6. The covered stent of claim 1, wherein when mounting the PTFE
tape, the section at which the PTFE tape is provided on the inside
of the cylindrical stent is increased or reduced in width.
7. The covered stent of claim 1, wherein when a plurality of
sections at which the PTFE tape is provided on the inside of the
cylindrical stent is provided, the sections are different from each
other in width.
8. A method of preparing a covered stent having bending
characteristics, the covered stent being prepared by using a jig in
which a cylindrical rod that has a same or similar diameter as an
inner diameter of the cylindrical stent having rhombic openings
that are formed by weaving shape-memory alloy wires alternatively
with a plurality of interlocking portions and a plurality of
intersection portions such that the rhombic openings are changeable
in size by external force, is coated with a coating solution of
silicone or a similar lubricous material on a surface thereof and
is dried, the method comprising: winding PTFE tape on the jig at
sections divided in a lengthwise direction of the jig with an
interval; fitting the cylindrical stent over the jig taped with the
PTFE tapes at the sections; winding a PTFE tape on an entire outer
surface of the cylindrical stent fitted over the jig; applying heat
and pressure by using a heating and pressurizing device after
completion of the winding the PTFE tape on the entire outer surface
of the cylindrical stent; allowing the PTFE tape provided at the
interval on an outside of the cylindrical stent to remain free
relative to the cylindrical stent because no PTFE tape is provided
at the interval to be bonded to the PTFE tape, whereas the PTFE
tape provided on an inside of the cylindrical stent and the PTFE
tape provided on the outside of the cylindrical stent are bonded to
each other through the rhombic openings of the cylindrical stent;
and removing the jig from the cylindrical stent.
9. The method of claim 8, wherein the interval at which no PTFE
tape is provided on the inside of the cylindrical stent is provided
in plural.
10. The method of claim 8, wherein the interval at which no PTFE
tape is provided on the inside of the cylindrical stent is
increased or reduced in width.
11. The method of claim 8, wherein when a plurality of the
intervals at which no PTFE tape is provided on the inside of the
cylindrical stent is provided, the intervals are different from
each other in width.
12. The covered stent of claim 2, wherein when providing the PTFE
tape, the interval at which no PTFE tape is provided on the inside
of the cylindrical stent is increased or reduced in width.
13. The covered stent of claim 2, wherein when a plurality of
intervals at which no PTFE tape is provided on the inside of the
cylindrical stent is provided, the intervals are different from
each other in width.
14. The covered stent of claim 5, wherein when mounting the PTFE
tape, the section at which the PTFE tape is provided on the inside
of the cylindrical stent is increased or reduced in width.
15. The covered stent of claim 5, wherein when a plurality of
sections at which the PTFE tape is provided on the inside of the
cylindrical stent is provided, the sections are different from each
other in width.
16. The method of claim 9, wherein the interval at which no PTFE
tape is provided on the inside of the cylindrical stent is
increased or reduced in width.
17. The method of claim 9, wherein when a plurality of the
intervals at which no PTFE tape is provided on the inside of the
cylindrical stent is provided, the intervals are different from
each other in width.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a covered stent
and a preparation method therefor. More particularly, the present
invention relates to a covered stent and a preparation method
therefor, wherein the covered stent is capable of widening a
stenosed site by being implanted in the stenosed site caused by a
lesion occurring in various organs such as the biliary tract, the
esophagus, the respiratory tract and the ureter, or in a
transjugular intrahepatic portosystemic shunt, is capable of
maintaining a bent state in accordance with a shape of a lumen even
when being implanted within the lumen in a bent state, and is
capable of preventing a stent having a long length, such as an
esophageal stent or an obesity-preventing stent to be implanted in
the esophagus, from twisting.
BACKGROUND ART
[0002] In general, stents are implanted in the internal organs so
as to push the lesion site and widen the stenosed organ. Such a
stent is configured with a hollow cylindrical body having a
plurality of rhombic openings by weaving one or more shape-memory
alloy wires in an overlapping manner. Recently, various kinds of
stents having different shapes have been developed.
[0003] Such a stent tends to remain straight, so there is a problem
in that when the stent is implanted within a meandering tubular
organ in the human body, the organ is brought to be
straightened.
[0004] In an effort to solve the above-mentioned problem, Korean
Patent No. 10-0457629 disclosed a stent capable of being maintained
in a bent state.
[0005] With reference to FIGS. 1 to 3, the stent configured with a
rhombic opening 5 is formed by weaving different wires 1 and 2
alternatively to each other with an interlocking portion 3 and an
intersection portion 4.
[0006] When the stent 6 is bent under the action of external force,
the wires 1 and 2 travel respectively such that the rhombic opening
5 is reduced or increased in size, thus the stent is maintained in
the bent state.
[0007] Accordingly, the stent 6 is maintained in the bent state in
such a manner as to be implanted within meandering tubular organs
in the human body.
[0008] However, the stent 6 is problematic in that an invasively
growing lesion may grow through the rhombic opening 5 of the stent
6 when the stent is implanted in an internal organ where a growing
lesion is present, thereby obstructing the movement of food, blood,
various body fluids such as biliary fluid, etc. inside a passage of
the stent 6.
[0009] In an effort to solve the above-mentioned problem, as shown
in FIG. 4, there is provided a covered stent 8 coated with silicone
or PTFE 7 on inner and outer surfaces of the stent, which has a
different shape from the stent 6.
[0010] Such a covered stent 8 is advantageous in that the rhombic
opening 5 is blocked by a coating layer of silicone or PTFE 7, so
it is possible to prevent invasion of the lesion into the covered
stent 8, and is thus mainly implanted in organs having a lesion
site that continues to grow.
[0011] However, there is a contradictory problem in that the
coating layer of silicone or PTFE 7 blocks the rhombic opening 5,
and at the same time completely fixes wires 1 and 2 that comprise
the rhombic opening 5, such that the wires 1 and 2 are prevented
from traveling freely even when external force is applied, and thus
the covered stent 8 cannot be maintained in the bent state.
[0012] Thus, the covered stent 8 has the same problem of being
maintained in the bent state as that of a conventional stent that
tends to be returned to the straight shape, whereas the covered
stent is employed in the meandering internal organs.
[0013] In an effort to overcome such disadvantages, Korean Patent
No. 10-1006990 has been disclosed.
[0014] With reference to FIG. 2, this prior art patent discloses a
method in which a stent 6 is configured with a plurality of rhombic
openings 5 that are formed by weaving different shape-memory alloy
wires 1 and 2 alternatively with a plurality of interlocking
portions 3 and a plurality of intersection portions 4 such that the
rhombic openings 5 are changeable in size by external force, and
which is subjected to heat treatment. Then, as shown in FIG. 5,
tapes 10 of PTFE or a similar material are wound at sections M
divided in a lengthwise direction of the stent 6 with an interval N
so that the coating layer 12 of silicone or a similar material is
prevented from being coated on the interlocking portions 3 and the
intersection portions 4 comprised of the stent 6 wound with the
tape 10, and the rhombic spaces 5. Thus, uncoated interlocking
portions 3, intersection portions 4, and the rhombic spaces 5 can
be freely changed in size by external force so as to be maintained
in the bent state.
[0015] With reference to FIG. 6, the stent 6 having bending
characteristics is prepared by: a process of forming the plurality
of rhombic openings 5 that are formed by weaving different
shape-memory alloy wires 1 and 2 alternatively with the plurality
of interlocking portions 3 and the plurality of intersection
portions 4 such that the rhombic openings 5 are changeable in size
by external force, and which is subjected to heat treatment for
storing a shape of the stent 6; a process of preparing a jig 70 in
which a cylindrical rod 50 that has a same or similar diameter as
an inner diameter of the stent 6 is coated with a coating solution
60 of silicone or a similar lubricous material and is dried; a
process of fitting the stent 6 over the jig 70; a process of
winding the tapes 10 of PTFE or a similar material at the sections
M divided in the lengthwise direction of the stent 6 with the
interval N on the interlocking portions 3 and the intersection
portions 4 of the stent 6, and thereby forming the rhombic spaces
5; a process of coating the stent taped with the tapes 10, 6 over
the jig 70 with the coating layer 12 of silicone or the similar
material so that the taped sections of the stent 6 remain free
relative to the coating layer 12; and a process of removing the
stent 6 subjected to the coating from the jig 70 and drying the
coating layer 12 coated on the stent 6.
[0016] However, such the stent 6 is problematic in that since an
upper surface of the tape 10 of PTFE is coated with the coating
layer 12 of silicone, the tape 10 and the coating layer 12 are
separated from each other due to heterogeneity.
[0017] Moreover, an upper surface of the tape 10 of PTFE is coated
with the coating layer 12 of silicone, so there is a problem in
that although it is required that the stent be maintained in a bent
state after being bent, it is difficult for the stent to be
maintained in the bent state due to a property of returning to the
original shape, which is possessed by the coating layer 12 of
silicone.
[0018] In addition, since an inside of the stent is coated with the
coating layer 12 of silicone, it is difficult for the stent to be
maintained in the bent state after the stent coated with dried the
coating layer is bent, due to the said property of returning to the
original shape, which is possessed by the coating layer 12 of
silicone.
[0019] Furthermore, due to this reason, when the stent is bent at a
certain angle or more, twisting of the stent occurs due to the
coating layer 12 of silicone on the inside and outside of the
stent, so it is difficult for the stent to be returned to the
original shape, namely the straight shape, when the stent is
required to be returned to the original shape after being bent. In
order to solve these problems, as shown in FIG. 7, there has been
an attempt to expose a part of an outer portion of the stent to the
outside by removing the tape 10 of PTFE before the coating layer 12
of silicone coated on the upper surface of the tape 10 of PTFE is
dried.
[0020] However, in this case, since the outside of the stent is
exposed, the lesion grows into the stent through the rhombic
openings 5 when the stent is implanted within a lumen of the human
body. Thus, there is a further problem in that the growing lesion
forces the coating layer 12 of silicone on the inside of the stent
toward the inside of the passage of the stent, and thus the coating
layer 12 blocks the passage of the stent.
DISCLOSURE
Technical Problem
[0021] Accordingly, the present invention has been made keeping in
mind the above problems occurring in the related art, and the
present invention is intended to propose a covered stent capable of
being maintained in a bent state and preventing invasion of the
lesion into the covered stent of the present invention by solving a
problem of a conventional stent having bending characteristics.
Technical Solution
[0022] In order to achieve the above object, according to one
aspect of the present invention, there is provided a covered stent,
wherein pieces of PTFE tape made of the same material can be
maintained in a bonded state with each other through only a partial
bonding on the inside and outside of a cylindrical stent, so it is
possible to prevent the pieces of PTFE tape from being separated
from each other. Due to this, the PTFE tape can be kept in a state
of covering an entire outer surface of the cylindrical stent so it
is possible to prevent invasion of a lesion into the cylindrical
stent, moreover, the PTFE tape is allowed not to be provided at a
part of the inside of the cylindrical stent so that the PTFE tape
provided on the outside of the cylindrical stent and the
cylindrical stent can remain free with respect to each other, and
thus the cylindrical stent can be freely maintained in the bent
state.
Advantageous Effects
[0023] According to the present invention having the
above-described characteristics, the present invention maintains
excellent bending characteristics so it is possible to be implanted
within a bent lumen in accordance with the degree of bending of the
lumen. Moreover, since a PTFE tape covers on an entire outer
surface of a cylindrical stent, it is possible to prevent invasion
of a lesion such as growing cancerous cells inside a covered stent
of the present invention even though the covered stent is implanted
within any part of a lumen. In addition, pieces of PTFE tape made
of the same material can be maintained in a bonded state with each
other through only a partial bonding on the inside and outside of
the cylindrical stent such that it is possible to prevent the
pieces of PTFE tape from being separated from each other. Due to
this, the PTFE tape can be kept in a state of covering the entire
outer surface of the cylindrical stent.
DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a view showing a configuration of a conventional
stent.
[0025] FIG. 2 is a partially enlarged view of part A shown in FIG.
1.
[0026] FIG. 3 is a partially enlarged view of part B shown in FIG.
1.
[0027] FIG. 4 is a cross-sectional view showing a covered stent in
the related art.
[0028] FIG. 5 is a view showing a configuration of a stent having
bending characteristics in the related art.
[0029] FIG. 6 is a view showing a process of preparing the stent
having bending characteristics in the related art. FIG. 7 is a view
showing a configuration of the stent having bending characteristics
in the related art.
[0030] FIG. 8 is a view showing a process of preparing a stent
having bending characteristics of the present invention.
[0031] FIG. 9 is a partial cross-sectional view showing an inside
of the covered stent of the present invention.
[0032] FIG. 10 is a view showing a configuration of the covered
stent having bending characteristics of the present invention.
[0033] FIGS. 11 and 12 are views showing another embodiment of the
present invention.
[0034] FIGS. 13 to 17 are photographs showing bending
characteristics of an actual product according to the present
invention.
[0035] FIGS. 18 to 22 are photographs showing bending
characteristics of an actual product according to another
embodiment of the present invention.
BEST MODE
[0036] Hereinafter, the present invention will be described in
detail with reference to the accompanying drawings. With reference
to FIG. 8, a cylindrical rod 50 having a same or similar diameter
as an inner diameter of a cylindrical stent (hereinafter referred
to as cylindrical stent 52 that will be manufactured as a covered
stent having bending characteristics of the present invention is
coated with a coating solution of silicone or a similar lubricous
material on a surface thereof and is dried to prepare a jig 70.
[0037] A process of winding PTFE tape 10 on the jig 70 at sections
E divided in a lengthwise direction of the jig 70 with intervals D
is carried out.
[0038] In this state, a process of fitting the cylindrical stent 52
having a plurality of rhombic openings 5 that are formed by weaving
different shape-memory alloy wires 1 and 2 alternatively with a
plurality of interlocking portions 3 and a plurality of
intersection portions 4 such that the rhombic openings 5 are
changeable in size by external force, over the jig 70 taped with
the PTFE tape 10 at the sections E is carried out.
[0039] In this state, a process of winding a PTFE tape 10-1 on an
entire outer surface of the cylindrical stent 52 is carried
out.
[0040] After completion of the process of winding the PTFE tape
10-1 on the entire outer surface of the stent 52, heat and pressure
are applied by using a heating and pressurizing device. By this
process, the PTFE tape 10 provided on an inside of the cylindrical
stent 52 and the PTFE tape 10-1 provided on an outside of the
cylindrical stent 52 are bonded to each other through the rhombic
openings 5 that comprise cylindrical stent 52, whereas the PTFE
tape 10-1 provided at the intervals D on the outside of the
cylindrical stent 52 remains free relative to the cylindrical stent
52 because no PTFE tape 10 is provided at the intervals D to be
bonded to the PTFE tape 10-1.
[0041] In other words, at the sections E, the PTFE tape 10-1
provided on the outside of the cylindrical stent 52 and the PTFE
tape 10 provided on the inside of the cylindrical stent 52 remain
bonded to each other with the cylindrical stent 52 interposed
therebetween. At the intervals D, the PTFE tape 10-1 provided on
the outside of the cylindrical stent 52 remains free relative to
the cylindrical stent 52.
[0042] A covered stent 100 having bending characteristics of the
present invention is prepared by the above processes and is removed
from the heating and pressurizing device, whereafter the covered
stent 100 having bending characteristics of the present invention
is removed from the jig 70. Here, since the outer surface of the
cylindrical rod 50 is coated with the coating solution 60 of
silicone or the similar lubricous material, it is possible to
easily separate the covered stent 100 from the jig 70.
[0043] With reference to FIGS. 9 to 10, the PTFE tape 10 remains
bonded to the PTFE tape 10-1 at the sections E on the inside of the
cylindrical stent 52 with the intervals D, whereas no PTFE tape 10
is provided at the intervals D on the inside of the cylindrical
stent 52, such that the PTFE tape 10-1 provided on the outside of
the cylindrical stent 52 has no PTFE tape 10 to be bonded thereto,
thereby remaining free with respect to the cylindrical stent 52.
Thus, the rhombic openings 5 formed by weaving wires with the
interlocking portions 3 and the intersection portions 4 at the
intervals D of the cylindrical stent 52 can be changeable in size
by external force. Thus, when the covered stent 100 having bending
characteristics of the present invention is bent in one direction,
the rhombic openings 5 located on a bent side are reduced in size
in such a manner as to be maintained in a bent state.
[0044] As a result, it can be seen that the covered stent 100
having the bending characteristics of the present invention is
capable of being maintained in the bent state at the intervals
D.
[0045] Here, the intervals D may be increased or reduced in number
and width as occasion demands, and may be varied to have different
widths D1, D2, and D3 as shown in FIG. 11.
[0046] Likewise, the sections E may be increased or reduced in
number and width as occasion demands, and may be varied to have
different widths E1, E2, and E3 as shown in FIG. 12.
[0047] With reference to FIGS. 13 to 16, it can be seen that the
present invention is in a straight state in FIG. 13, is maintained
in a slightly bent state in FIG. 14, is maintained in a more bent
state in FIG. 15 than in FIG. 14, namely is further bent from a
semicircle, and is maintained in a bent state when both ends are
bent until they almost come into contact with each other in FIG.
16.
[0048] Further, with reference to FIG. 17, it can be seen that the
present invention is maintained in a bent state when being bent in
an S-shape. Thus, it is indicated that the covered stent having
bending characteristics of the present invention can be maintained
in the bent state although it is a stent having a PTFE tape covered
thereon.
[0049] Moreover, with reference to FIG. 18, the present invention
can be applied to an expandable stent having an expanded inlet at
an end, and can be also applied to an expandable stent having
expanded inlet and outlet at both ends.
[0050] As described above, according to the present invention, it
can be understood that the present invention is a stent that
maintains excellent bending characteristics, and thereby can be
implanted within a bent lumen in accordance with the degree of
bending of the lumen.
[0051] In addition, since the PTFE tape 10-1 is provided on the
entire outer surface of the cylindrical stent 52, it is possible to
prevent invasion of a lesion such as growing cancerous cells inside
the covered stent 100 of the present invention even though the
present invention is implanted within any part of a lumen, thereby
being capable of performing intrinsic functions of a stent.
[0052] Thus, according to the present invention, pieces of PTFE
tape made of the same material can remain bonded to each other
through only a partial bonding on the inside and outside of the
cylindrical stent such that it is possible to prevent the pieces of
PTFE tape from being separated from each other. Due to this, the
PTFE tape can be kept in a state of covering the entire outer
surface of the cylindrical stent, such that it is possible to
prevent invasion of the lesion into the cylindrical stent.
Moreover, the PTFE tape is allowed not to be provided at a part of
the inside of the cylindrical stent so that the PTFE tape provided
on the outside of the cylindrical stent and the cylindrical stent
can remain free relative to each other, and thus the cylindrical
stent can be freely maintained in the bent state.
[0053] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS
TABLE-US-00001 [0054] 1, 2: wire 3: interlocking portion 4:
intersection portion 5: rhombic opening 10, 10-1: PTFE tape 52:
cylindrical stent 60: coating solution 70: jig 100: covered
stent
* * * * *